Potrebno je sa php izgenerisati niz sel_2 koji ce biti povezan sa vrednostima iz select 1
Code:
<select id="select_1" onChange="select_2()">
<option value="value_1">Option 1</option>
<option value="value_2">Option 2</option>
<option value="value_3">Option 3</option>
</select>
<select id="select_2" ></select>
<script type="text/javascript">
function select_2()
{
var sel1 = document.getElementById('select_1');
var sel2 = document.getElementById('select_2');
var sel_2 =new Array();
sel_2['value_1']=['OPTION 1','value','OPTION 1_1','value','OPTION 1_2','value'];
sel_2['value_2']=['OPTION 2','value','OPTION 2_1','value','OPTION 2_2','value'];
sel_2['value_3']=['OPTION 3','value','OPTION 3_1','value','OPTION 3_2','value'];
sel2.options.length = 0;
for (var i=0;i<sel_2[sel1.value].length;i +=2)
{sel2.options[i/2]=new Option(sel_2[sel1.value][i],sel_2[sel1.value][i+1],false);}
}
select_2();
</script>